ref: 7ef2abad32fe3b273f16eeb28d63a63229dca3a6 dir: /lib/std/slfill.myr/
pkg std = generic slfill : (sl : @a[:], v : @a -> @a[:]) ;; generic slfill = {sl, v for var i = 0; i < sl.len; i++ sl[i] = v ;; -> sl }